Albert Barnes on John 11:23

Thy brother shall rise again. Martha had spoken of the power of Jesus. He said nothing of himself in reply. It was not customary for him to speak of himself, unless it was demanded by necessity. It cannot be doubted that by rising again, here, Jesus referred to the act which he was about to perform; but as Martha understood it, referring to the future resurrection, it was full of consolation. The idea that departed friends shall rise to glory is one that fills the mind with joy, and one which we owe only to the religion of Christ.